A patch is seen on the jacket of a Transportation Security Administration official as he works at the automated screening lanes funded by American Airlines and installed by the Transportation Security Administration at Miami International Airport on October 24, 2017 in Miami, Florida.

How has airline travel changed through the decades? Click through to find out how different air travel looked way back when.

How has airline travel changed through the decades? Click through to find out how different air travel looked way back when.

Photo: Getty Images

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How airline travel has changed through the decades

1920s: Longer flight times

During the 1920s, commercial air travel was first introduced to passengers and was a new and exciting endeavor -- but it had its pitfalls. Less than 20 passengers were allowed per flight and planes only reached altitudes of 3,000 feet or less, which made flights much longer, Insider wrote. Ironically, traveling by train was much faster in those days.

In this April 1929 file photo, a cabin steward serves drinks to the passengers on an early French airliner that offered service to and from Le Bourget.

While they worked out the kinks to commercial air travel, passengers suffered drawbacks like chilly cabins, since many airplanes were made of uninsulated sheets of metal that shook loudly in the air. Without headphones, passengers just stuck cotton in their ears to make the flight more bearable.

File image of the first passenger plane for Berlin-London Air Service in 1923.

The first flight attendants were introduced in the 1930s to make flights more comfortable for passengers. In the earliest days of commercial air travel, flight attendants needed to be registered nurses should someone get sick during the flight, CNN wrote. They also helped tend to nervous passengers and sometimes help refuel the plane or even bolt seats to floor. Later during WWII, airlines began expanding their hiring requirements to include: Barbie-doll height and weight standards, girdles and heels worn at all times, and mandatory retirement by the age of 32.

File photo of an American Airlines flight attendant with a tray of food in 1935.

1930s: Planes would drop mid-air — but at least flights were more comfortable

It's no wonder flight attendants had to soothe the nerves of stressed-out passengers. In the 1930s, planes could suddenly drop hundreds of feet in a matter of seconds due to horrible turbulence, Gizmodo wrote. Despite stomach-turning drops, passenger cabins were more comfortable as padding and upholstered seating, sound-proofing and heating were introduced.

File photo of passengers on a de Havilland Flamingo plane in 1939. less

1930s: Planes would drop mid-air — but at least flights were more comfortable

It's no wonder flight attendants had to soothe the nerves of stressed-out passengers. In the 1930s, planes could suddenly drop

Commercial air travel dramatically changed during WWII, when aircrafts increasingly were designed for war. After the war ended, airports were built near major cities in Europe, like London Heathrow Airport, that was completed in 1946. Transatlantic flights became more frequent, especially from New York and London.

File photo of the interior of a Douglas DC-6 passenger airliner that show passengers and flight attendants in 1947. less

1940s: More transatlantic travel

Commercial air travel dramatically changed during WWII, when aircrafts increasingly were designed for war. After the war ended, airports were built near major cities in Europe,

In the 1950s, passengers could go to town when it came to seat reclining, unlike most commercial airlines today. According to USA Today, most airlines allow five degrees of recline in economy class with 30 to 31 inches of "pitch," or legroom (more on that later).

In the 1950s and 1960s, flights were way more expensive than they are today, but the food more than made up for it. Dining on flights could easily be a two to three hour affair with meals that could include caviar, cheese plates, lobster and steak. Cocktail carts were also part of the package; passengers could wash their meal down with champagne or whiskey.

Prior to the 1960s, flights were boring, with little entertainment options (booze can only take you so far). But by the time the 60s rolled in, in-flight movies became mainstream. According to Wired, Trans World Airlines became the first airline to offer regular in-flight movies by 1961.

The 1960s saw a new take on the flight attendant uniforms by introducing more designs like mini skirts and....

1960s: Flight attendant uniforms get skimpy

The 1960s saw a new take on the flight attendant uniforms by introducing more designs like mini skirts and....

Photo: Photoshot/Getty Images

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How airline travel has changed through the decades

... short shorts with go-go boots. In this 1972 file image, a Southwest flight attendant wore go-go boots and shorts, as required for the job. Additionally, flight attendants were hired based on attractiveness, weight and specific height. Later, they filed a lawsuit to fight against the dress code and won some of the first Title VII sex discrimination victories for women in the workforce, Slate wrote. less

... short shorts with go-go boots. In this 1972 file image, a Southwest flight attendant wore go-go boots and shorts, as required for the job. Additionally, flight attendants were hired based on ... more

Photo: Photoshot/Getty Images

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How airline travel has changed through the decades

1970s: Airlines get deregulated and flights get cheaper

In 1978, President Jimmy Carter signed the Airline Deregulation Act that phased out federal control of the nation's airlines. This meant that more people could afford air travel and airlines could offer more competitive prices.

1980s: You could take a private tour of the cockpit and meet the pilots too

First-time plane travelers could get a tour of the aircraft from flight attendants, and this included the cockpit. Both children and adults alike could meet the pilots, and kids received commemorative wing pins (sorry adults). Some flights today still allow children to meet the pilots on their first flight.

Smoking was allowed on air travel up until the 1980s, when it became a hot topic. President Ronald Reagan signed a law that prohibited smoking on domestic flights of less than 2 hours in 1988, and then in 1989 it became unlawful to smoke on domestic flights that were six hours in length. By Feb. 1990, after pressure from the Association of Flight Attendants, smoking became banned on all domestic travel with the exception of a few domestic flights more than 6 hours, according to the New York Times.

Remember those clunky phones attached to the seatbacks? In the pre-cell phone and Wi-Fi era, passengers could pay to make calls on Verizon Airfones from 30,000 feet in the air. The only problem? They frequently dropped calls. Delta was the first airline to introduce this new technology but, due to lack of passenger use, Verizon decided to shut down its phone service in 2006.

File photo of a woman reading on a passenger plane equipped with an Airfone, an air-ground radiotelephone service, in 1994.

After 9/11, President George W. Bush signed the Aviation and Transportation Security Act into law. It drastically changed security by requiring screenings of passengers and baggage, the expansion of the Federal Air Marshal Service and reinforced cockpit doors. Among other things, the amount of liquid/gels allowed in carry-on baggage was reduced significantly by 2006.

To up the ante, by 2010 airports began to install hundreds of Advanced Imaging Technology, or full-body scanners, in order to detect non-metallic weapon explosives and other threats that could be concealed under layers of clothes, as noted on the TSA website.

Some airlines have considered removing in-flight entertainment, or seatback screens, from shorter flights to be more cost efficient. According to the New York Times, installing a seatback screen can cost as much as $10,000 per seat and also adds weight to the aircraft. Some airlines already offer onboard streaming, where passengers can watch shows from their own devices.

Forget the Golden Days of Flight. Modern airlines have reduced the amount of pitch (aka legroom) in economy class significantly since its heyday. Today, the average pitch is about 30 to 31 inches. In February, United Airlines announced that it plans to add 21 more seats onto its domestic Boeing 757-300s by July, and other airlines like Delta, American and Southwest have also rolled out their own version. Read our coverage here.

Federal air marshals have for years been quietly monitoring small numbers of U.S. air passengers and reporting on in-flight behavior considered suspicious, even if those individuals have no known terrorism links, the Transportation Security Administration said on Sunday.

Under a sensitive, previously undisclosed program called "Quiet Skies," the TSA has since 2010 tasked marshals to identify passengers who raise flags because of travel histories or other factors and conduct secret observations of their actions - including behavior as common as sweating heavily or using the restroom repeatedly - as they fly between U.S. destinations.

The Boston Globe first revealed the existence of the Quiet Skies program on Sunday. In response to questions, TSA spokesman James Gregory offered more details of the program's origins and goals, comparing it to other law enforcement activities that ask officers to closely monitor individuals or areas vulnerable to crime.

"We are no different than the cop on the corner who is placed there because there is an increased possibility that something might happen," Gregory said. "When you're in a tube at 30,000 feet . . . it makes sense to put someone there."

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The Federal Air Marshal service is under a government investigation, The New York Times reported. Veuer's Sam Berman has the full story.

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The TSA declined to provide complete information on how individuals are selected for Quiet Skies and how the program works.

According to the TSA, the program used travel records and other factors to identify passengers who will be subject to additional checks at airports and, sometimes, be observed in flight by air marshals who report on their activities to the agency.

The initiative raises new questions about the privacy of ordinary Americans as they go about routine travel within the United States and about the broad net cast by law enforcement as it seeks to keep air travel safe.

Gregory said the program did not single out passengers based on race or religion and should not be considered surveillance because the agency does not, for example, listen to passengers' calls or follow flagged individuals around airports.

But during in-flight observation of people who are tagged as Quiet Skies passengers, marshals use an agency checklist to record passenger behavior: Did he or she sleep during the flight? Did he or she use a cellphone? Look around erratically?

"The program analyzes information on a passenger's travel patterns while taking the whole picture into account," Gregory said, adding "an additional line of defense to aviation security."

"If that person does all that stuff, and the airplane lands safely and they move on, the behavior will be noted, but they will not be approached or apprehended," Gregory said.

He declined to say whether the program has resulted in arrests or disruption of any criminal plots.

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Hugh Handeyside, senior staff attorney with the American Civil Liberties Union's National Security Project, called on the TSA to provide more information about the program to passengers.

"Such surveillance not only makes no sense, it is a big waste of taxpayer money and raises a number of constitutional questions," he said. "These concerns and the need for transparency are all the more acute because of TSA's track record of using unreliable and unscientific techniques to screen and monitor travelers who have done nothing wrong."

The TSA, which was created soon after the Sept. 11, 2001 terrorist attacks, screens on average more than 2 million passengers a day.

While the agency is tasked with a weighty public safety mission, it has at times been publicly rebuked for being intrusive and abusive at airport checkpoints. It has been accused of doing little to enhance security while subjecting passengers to searches or questioning.

In 2015, the Department of Homeland Security's inspector general found that undercover agents were able to slip fake bombs past TSA screeners about 95 percent of the time. A year later, the flying public was in an uproar over long lines to move through security screening.

But TSA officials have said that ensuring public safety while keeping passengers moving has made their work difficult.